Aquamarine Mining

by Sheweta Dhanuka

The mining process starts from carrying out the geological site investigation and environmental impact assessment (EIA) of the mines that might offer aquamarine gemstone. Then, the landform is defined by the gently moving the surface with a smooth wave like motion and is raised above the sea level. This is referred as Geomorphology.

Aquamarine is " The Gem of the Sea ". It is a light bluish green precious
stone. In Latin, 'aqua refers to water' while ' mare means sea' so together
when we join 'aqua' and 'mare' it becomes aquamarine. Therefore, aquamarine
means sea water. As the name suggests, it possess all the different shades of
the sea water - light blue colour to dark with the touch of green in all the
possible variations.

With the increase in the size of stone, the colour becomes more light and
transparent. Aquamarine contains tiny amount of iron, which is responsible for
giving it the colour. Sometimes it is heated or irradiated to get the desired
colours from the pale aquamarine crystals. The price of the stone rises with
the intensity of it's colour.

The premier source of aquamarine gemstones having dark blue shades to lighter
ones is Madagascar. Gemstone's country Brazil, supplies good quantity of
aquamarine stones. Other aquamarine mines are found in the African countries of
Tanzania, Kenya, Mozambique and Nigeria. This gemstone is procured from the
island of Sri Lanka, USA and Russia too.

Also mines at Gilgit in Pakistan and few parts of Afghanistan holds large
amounts of aquamarine. Mwami, Hurungwe, Pfungwe and Mtoko are yet other sources
situated in different parts of the world. All the mines are mostly above the
sea level. The mining process starts from carrying out the geological site
investigation and environmental impact assessment (EIA) of the mines that might
offer aquamarine gemstone.

Then, the landform is defined by the gently moving the surface with a smooth
wave like motion and is raised above the sea level. This is referred as
Geomorphology. The identified area contains precambrian metamorphic rocks under
it. These rocks are composed of many minerals like quartz, feldspar, mica,
garnet, biotite etc. And it holds many gemstones within it. Metamorphic rocks
comprises some veins called as Pegmatite veins that host aquamarine crystals.

These veins are sheared and varies from 10m to 40m in thickness. Aquamarine
crystals are of cabochon to facet grade varieties and are quite clear bearing
few inclusions. Aquamarine mineralisation occurs within the pegmatites veins.
The centre of the pegmatite, being massive is fractured and banded. The veins
are fractured through opencast mining method using pneumatic tools.

Compressor, jack hammer, picks, shovels, chisels, ladders, etc are few to name.
The mining then is augmented by a bulldozer to mine the aquamarine. Once the
gemstone is free of the rock, it is collected and cleaned off with the water.
It is crucial to mention that aquamarine mining is quite environment friendly.
Toxic and environment-unfriendly chemicals and materials like mercury and
cyanide are not used for mining of aquamarine. These are used in mining of gold
and base metals.

As learnt above, the metamorphic rock containing aquamarine is braked apart into
large pieces with the tools that inserts the air/gas pressure inside the rocks.
With the pressure the rocks splits, gems are procured and later washed with
water. Thus, mining is simple having no harmful or adverse effects. And also
after exhausting the reserves, water is pumped from the pits and purified using
chlorine.

The pits are filled with waste of rock. Above it, a layer of soil is laid having
the thickness of 2m to 4m. After the soil gets settled, grass, relevant trees
and plants are planted. The vegetation is taken care off to ensure growth for
couple of years. Other wastes, such as plastics, waste paper, metal cans etc.,
is collected in separate metal boxes and later transported to recyclers or
dumped at dumpsites. In case any petrochemical pollutant passes to water stream
then the streams are well cleaned. In all, after the work is done the place is
well organized and regains it's natural look.

Aquamarines collected from the mines are called as rough aquamarine. These are
then sorted for size, shape and colour. After the sorting, it undergoes "gem
processing" - the most critical step. The process of transforming the "rough"
gemstones into beautiful and attractive gems takes lot of experience, hard work
and potential. In order to optimize the rough, it is cut into long and thin
slabs. Usually, aquamarines are free from inclusions and fractures so it
proceeds directly to the next stage of gem processing. But, in case it has any
fractures then those are removed with a diamond saw blade and the process is
called sawing.

In the next stage the stones are outlined on the slab and the shapes are cut. It
being a resistant stone, cutters give new and modern cuts. This process is
called as pre-forming. The pre-forming is done on diamond grinding wheels
lubricated by water. After getting the shape sometimes aquamarine is coloured
by the colour centers. Mostly, this gemstone posses natural blue green to light
sky blue colour. Thus, no further colouring is required. But, when the stone is
yellow or pale, it is heat treated to produce the demanding bluish green
colors. The heat treatment is performed in specialized laboratories by the
experts. Thus, the colouring results are stable and permanent.

In this way aquamarine completes a long journey from metamorphic rocks to the
showrooms to be part of our jewelry. It is really a valuable stone that used to
be considered as the treasure of the mermaids of the sea. Aquamarines are
widely used in all the jewelry items making women more beautiful in the entire
world. So here is just one small tip- when making the purchase of aquamarine
jewelry look for the light sparks it emits in daylight. The sparkle should be
bright and colourful. So happy buying and enjoy wearing the treasure of the sea
!!!!